The National Institute of General Medical Sciences (NIGMS), one of the National
Institutes of Health, supports all research featured in this
digest. Although only the lead scientists are named, coworkers
and other collaborators also contributed to the findings.
To read additional news items, visit NIGMS
Research Around the Nation.

Cool Image: Colorful Communication

The marine bacterium Vibrio harveyi
glows when near its kind. This luminescence,
which results from biochemical reactions,
is part of the chemical communication
used by the organisms to assess their
own population size and distinguish themselves
from other types of bacteria. But V.
harveyi only light up when part of
a large group. This communication, called
quorum sensing, speaks for itself here
on a lab dish, where more densely packed
areas of the bacteria show up blue. Other
types of bacteria use quorum sensing to
release toxins, trigger disease, and evade
the immune system. Courtesy of Bonnie
Bassler, a microbial geneticist at Princeton
University.

Chicken Eggs Offer Better Way to Produce Important Drug

In recent years, a new class of drugs called monoclonal antibodies has become
an important method for treating cancer
and other illnesses. Currently, monoclonal
antibodies are produced by inserting the
genes encoding these proteins into cultured
hamster or mouse cells. But the high cost
of this technique has prompted scientists
to look for a better way. With NIGMS funding
in the form of a small business innovation
grant, biologist Lei Zhu of Origen Therapeutics
has figured out how to make monoclonal antibody
drugs in chicken eggs. She found that extracting
the therapeutic proteins from egg whites
was straightforward and efficient. In lab
tests, the antibody proved to be even more
effective at killing cancer cells than were
antibodies made by traditional means.

Disease-Causing Fungi Evade
Detection by Changing Look

Caption:
Colonies of Candida albicans,
the most common disease-causing
fungus in humans. Courtesy of Felice
Frankel.

Just as friends recognize you by your outward
appearance, your immune cells recognize
a microbe by its surface features. But fungal
microbes, which are now the fastest growing
cause of hospital-acquired infections, can
rapidly change parts of their surfaces and
escape immune detection. A team of geneticists
led by Gerald Fink of the Whitehead Institute
for Biomedical Research, has discovered
how fungi transform themselves. They make
use of DNA elements known as tandem repeats—recurring,
identical units of DNA found on chromosomes.
By varying the number of repeats in genes
that code for cell-surface proteins, fungi
change the way they look, allowing them
to go incognito in the body. These findings
help explain why fungal infections can be
such a problem and could lead to new targets
for drugs that fight these infections.

Worm Offers Clues on Plague,
Deadliness

Caption:
C. elegans, the tiny
worm that Aballay uses to study
plague bacteria, as featured on
the cover of EMBO Reports.
Courtesy of Diane Jarsocrak.

In the 14th century, one-third of Europe’s
population died from the bacterium that
causes plague, Yersinia pestis.
Today, this bacterium is on a short list
of possible bioweapons. Microbiologist
Alejandro Aballay of Duke University Medical
Center tracked down individual proteins
that make plague so lethal. In addition
to using mice, he developed a new model
system for studying plague—the microscopic
roundworm, Caenorhabditis elegans.
His work suggests that plague bacteria
use similar methods to infect worms and
humans, including a previously uncharacterized
family of proteins. Because C. elegans
develop quickly and are easy to manipulate
genetically, using them to study plague
may rapidly accelerate our understanding
of how the bacterium causes plague and
may help mitigate any future outbreaks.

Profiles in Discovery: Malaria and Protein Design

How does malaria, the oldest disease
known to humankind, spread so quickly
through the developing world? What secrets
hide inside a parasite’s DNA that
enables it to ignore antimalarial drugs?
Geneticist Dyann Wirth (right) at the
Harvard School of Public Health is investigating
the answers. Read about her global research
in “Science Without Borders”
in the September 2005 issue of the NIGMS
publication Findings. Also check out "The
Family Business" to learn how world-class
computational biologist David Baker (left),
who never took a computer class in his
life, uses a self-designed computer program
to model protein shapes and design proteins
never before found in nature.

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Biomedical Beat is produced by the Office of Communications and Public Liaison of the National Institute of General Medical Sciences. Some of the research briefs in this digest were generated from university or national laboratory news releases. For more information about Biomedical Beat, please contact the editor, Emily Carlson, at carlsone@nigms.nih.gov or 301-594-1515. To talk to someone at NIGMS about this research, call 301-496-7301. The material in this newsletter is not copyrighted and we encourage its use or reprinting.